Oldsprepp

With a 455 450hp (not rwhp) in a 3750lbs with Dragradials. ?

0-60=?

1/8 =?
1/4 =?

if someone has a similar car with about that set up?

Redog

http://www.race-cars.net/calculators/et_calculator.html

Assuming 20% drivetrain loss (375 at the wheels) you're looking at 12.549 @ 108.61 MPH

Rallye469

Did you arrive at 450 hp with a dyno...or just a knowledgeable guess?

There's more to it then hp, tires & weight but I guess the above # is a good # to shoot for.

Oldsprepp

No just trying to deside how much hp i need to get to the numbers a want to be at....i want to land around 12secs a 1/4mile.

i dont want to waste money underbuilding or overbuilding the engine..
thx for the answers..

Rallye469

Gotcha...Well if you can get it down to 3750 with you in it mid 12's
shouldn't be too difficult. Some nice heads and a smart cam choice
will land you there squarely.

That calculator is generous...
Between my dyno #'s and my trap speed it shows I'm only loosing 16.8%
through the drive line.
My car is NOT that efficient.
With a TH400 & a 9" rear I thought it would be around up around 20-25% loss.

Redog

I've heard some places say 17% loss and others say 23% loss in the drive train. 20% is right in the middle

88 coupe

439 HP at 5400 RPM.

3950 lb.

Bias ply street tires.

11.9xx at 114 miles per hour

Close enough?

Norm

Oldsprepp

oh nice figures! thx for the info!

Rallye469

88 coupe

Glad I could help. If you have any further questions, just ask.

Norm

88 coupe

Read the whole post before you start more of your BS. Or did you? Did you use those childish bold fonts to divert everyones attention from the other part of the same post?

Either way, here it is again:

450 HP = 450 HP, regardless of the displacement. Do you think 439 HP is not "similar" enough?

Conventional thinking is that: 100# = About one tenth. Do you think 3950# is not "similar" enough?

Norm

Rallye469

I just wonder if you read the post Norman.
The whole post.

I was just asking if that 439 HP was on an engine dyno or a chassis dyno.
439hp is close enough to 450hp for me...
It's a fair comparison.

But 439 hp at the crank won't put you at 11.9 in a 3950lb car
and 439 hp at the rear wheels wasn't what he was asking about.

So- I'm not starting BS, I am calling BS Norm.
Plain & simple.

88 coupe

Read this entire thread again.

Then quote the part where someone said the OP was not asking about flywheel HP?

Then read this post, again.

NormNote the applicable exceptions. They are:

Then quote the part where I said anything about a “chassis dyno”, as opposed to a “real dynamometer”.

Norm.

Rallye469

That's the point.
You didn't.

So...
Which is it?
He was not asking about RWHP.
Says so in his first post in this thread.
I quoted it and bolded 'not RWHP' again.

So which is it Norm?

88 coupe

Yes, it is.

No, I didn't.

No, he wasn't.

Yes, it does.

Yes, you did.

Yes, you did.

Norm

Rallye469

That clears it all up.

344870M

I had a 66 Starfire for my first car. I remember reading (and not knowing what it meant) a "taxable" horsepower figure for the car. I think it was about 75. This means (I guess) that there was about 300 horsepower at the rear wheels. I raced the car in the eighth mile and ran my quickest run at 9.36 seconds. Not bad for a 4200lb car with 3.08/3.23 (?) gears and an auto. Can someone w/a Starfire confirm that number?

This calculator would then put my big ol Starfire at 14.04 in 1/4 with a trap speed of 97. It was pushing 75 in the eighth.
That sounds about right.

However... My 70 W30 4 spd w/4.33's... I would hope/think that this car has more rear wheel hp than the Starfire. They're both rated at 375. Sure. OK.

Never raced it, but using figures I've read. A 3750 lb car running the recorded time of 13.88 puts r/w hp at 257. That's about -30% loss. And makes the car a dog. It is NOT a dog. And it gets ALL OVER that big Starfire. I find it hard to believe that after all that was done to the W machines it would only run .16 seconds quicker. Or am I figuring something wrong.
The original owner told me the car ran high 12's. But then memories get fuzzy don't they.


Here's a clip of the W from a few years ago. She was loosing vacuum out the back of the intake so she wasn't running as well as she could.

http://www.youtube.com/watch?v=5y_OKnABGJ0

88 coupe

Simply put, it's a different method of measuring power output. Nothing to do with this topic.

In order for it to work, the correct numbers must be entered, and the cars configuration must match the one the formula represents.

Because we are using different numbers, the formula has nothing to do with this topic.

What they were "rated" at, depended largely on marketing needs at the time, and the figure was not directly related to the actual power output of a given engine.

The thread owner was looking for hard numbers, not fairy tales. As you can see, he got them in post #7, and the thread was finished (in more ways than one) with #8.

Posts #2 through #6 and from #9 on, would be the cause of your confusion.

That's about what they did. All it took was a pair of slicks and a competent driver.

Norm

Rallye469

RAC or Taxable Horsepower:
I never knew that...just always thought it was an industry term that loosely described a line of automobiles horsepower ratings.

Despite what some think, that's pretty much what this thread is about.
(or at least it's a huge sidebar)
Deducing a 1/4 mile time from a given HP rating.

Ding! Ding! Ding!

That's the problem. Taxable, gross, brake/net/crank, rwhp/effective horspower are all measured differently.

Oldsprepp was smart enough to ask very specifically what 1/4mile #'s
could be expected from a RWHP rating...a specific type of measurement.
Others, the more obtuse, don't really care or at the very least,
don't care to specify what type of rating they have used.

88 coupe

Yes, he was.

Not, what he specifically asked for.

Here it is, again:

He, very specifically, asked for something other than RWHP.

He did not, very specifically, ask for something other than Taxable HP. He could not have, because it has nothing to do with his thread.

Here is, specifically, what he did ask for:

He got, very specifically, what he, very specifically, asked for.

Not The kind of schoolyard BS, I would expect, from an adult (or an "engineer"). More like what a BS artist resorts to, when he/she gets a hand slapped.

In my experience, an engineer will carry on a logical/rational/mature discussion, even when he is wrong. Right, Joe?

Here it is, again:

On second thought, after three times, I'll just leave you to find it for yourself.

Yes, it does.

Norm.

Rallye469

Oh Norman...

Once more:


If (and I'll ask again oh great one) that 439hp is at the crank
you did not go 11.9.

-or-

If you went 11.9, that 439hp was measured at the wheels.

No need to give a straight answer this time either...
You'll just find something else to criticize about they way
I asked or spelled or punctuated or bolded or underlined
or italicized or thought or wrote or assumed or asked
or learned or didn't learn or defined or...

BTW...What's wrong with engineers? Someone has to drive the train!
Choo! Chooooooooo!

88 coupe

You are free to ask anything you wish, no matter how childish your question might be.

Actually, that same engine, in a 3900# car, turned an 11.800 @ 114.52.

When mounting a challenge, such as this one, it is customary to provide some sort of data that might justify your allegation.

Do you still beat your wife?

Norm

Rallye469

Let's hear it for Norm folks!!!
He's managed to dodge the question again
and this time, wanting to up the ante, has
thrown in another number from the land
of make believe. -A stunning 11.8!

Let me guess. You ditched the bias-plys
and made this run on space saver doughnuts?

Oldsguy

No longer usefull information here guys. Take it to the PM.